In the same as with rigid frame-structured bicycles unsuitable for being folded the bicycle has a frame structure fitted with a front wheel and a rear wheel, a handlebar column fitted to the frame structure, handlebars fitted to the handlebar column, a seat post also fitted to the frame structure and a seat fitted to the seat post, furthermore it has a drive chain, and crank arms fitted with pedals as well as a drive mechanism including chain wheels.
The frame structure is assembled from parts that, by releasing the aforementioned fixing components, are capable of movement as compared to each other, characteristically relative angular rotation, for the purpose of realizing the relative angular rotation there are structural elements, favorably hinge joints, permitting this inserted between the parts of the frame structure that are connected to each other.
Bicycles are transport and sport devices known for a long time with a light metal frame. In general they are chosen as transportation in order to reach destinations at a relatively short distance. They have special significance in urban transportation, where, as opposed to motor vehicles that use liquid fuel, due to both environmental and parking aspects and bicycles have clear advantages.
If the bicycle has to be taken for a longer distance and used there for transport, tourism or competition sport purposes, then the significant part of the longer distance is overcome with a transportation vehicle. In such cases it is favorable if the bicycle takes up as small a space as possible. In this way various types of foldable bicycle were created, which now have been around for a century.
The common structural idea of the uncountable number of versions of foldable bicycle developed is based on that their frame structure needs to be established from a frame that has at least folding axis. In general the folding axis, or the most important one if there is more than one axis, is positioned vertically or more rarely horizontally. The solutions with a vertical folding axis usually have two frame elements that can be folded next to each other around a hinge joint with a vertical axis. For this the main part of the frame is divided at approximately the middle for the purpose of being able to position the hinge joint. Besides their advantageous simplicity an unfavorable aspect is that folding requires many movements, and when being used they create a risk of accident mainly because clothing can be caught up.
The versions with a horizontal folding axis are partially simpler and partially more complex than the previous versions. Their operation is simple, however, their structural construction as this is a multi-hinged mechanism is clearly complex. It is also unfavorable that when folded the wheels are positioned one behind the other, so they cannot be transported by rolling. Due to the complexity of their structure their manufacture is costly.
In the case of a certain type of frame with a horizontal hinge axis they have overcome the issue of the wheels being behind one another. In this way the folded vehicle can be rolled as wheeled luggage. However, the horizontal hinges demand sliding connections or detachable frame elements, due to which in their folded state, on the one hand, the vehicle has an unfavorable geometric shape and, on the other hand, is unusually large.
Special solutions that cannot be categorized in any of the previous versions also exist. Among them there is a type that does not demand the division of the main part of the frame structure. This apparent advantage, however, also comes with many more disadvantages. Primarily because their structure and operation is complex, and their production is costly, and due to this not a single one of these types of vehicle has become widespread.
A special foldable bicycle from the recent decades is presented in patent specification registration number HU 185.269. Its specialness is conspicuous in two respects. On the one hand, because it is fitted with a series of solar cells, and so they are not only suitable for providing power to the usual fittings of the bicycle, there is also the possibility for battery-powered drive. Another special feature is that it can be folded into the shape of a bag. Due to both of these special features, mainly due to the latter, there structural construction is complex. Changing the bicycle from folded-out state to folded-up state (and vice versa) is also complicated and takes a great deal of time.
“Foldable bicycle” with registration number HU 220.140 has a significantly simpler structure than the previous version”. However, it is unfavorable that neither the main frame between the wheels, the double cross-tube nor the handlebar column can be shortened when folding, and so, in this way, its transporting size is hardly smaller when in folded-out state for use. For the purpose of folding to as small a size as possible both the handlebar column and the seat post are telescopic in the solution according to Hungarian patent application number P 0203480. The main parts of the frame are connected to each other with spring connections, but the optimal harmonization of the spring characteristics and their permanence over time cannot be guaranteed.
In the case of patent specification registration number EP 1 494 916 for the purpose of the efficiency of folding the handlebars are broken up with hinges, the seat part has a telescopic structure, and the front wheel can be folded to the frame cross bar and the rear wheel can be folded to the seat post. It is unfavorable, however, that in transportation state the stability of the bicycle has to be separately ensured.
More or less similar structural and use disadvantages can be determined in the cases of European patent specifications registration numbers EP 1 575 823 B1 and EP 1638 835 B1 in connection with their solutions. The common deficiency of these and of the known solutions in general is that they cannot be stored vertically or in a way that saves space, and in the case of most of them a relatively large number of movements are needed to fold them up and fold them out.
The relatively most developed type of the known foldable bicycles can be seen in patent specification registration number U.S. Pat. No. 7,140,629. Its main advantage comes from the horizontal arrangement of the central hinge axis, which results in a rigidity that is much greater than in previous versions. When compared to vertical hinge axis solutions this is especially apparent in that and when a heavy person rides standing up on an uneven road. In the case of old foldable bicycles at such times there was a risk of the bicycle breaking, which the given idea overcomes. Its disadvantages, however, are that a great deal of friction has to be overcome when folding up and unfolding the bicycle, which makes use difficult, furthermore, that the seat post does not close sufficiently into the rear frame part and that in folded up state the axles of the two wheels are at an angle to one another, which makes rolling impossible.
In view of the foregoing, at least one object is to develop a foldable bicycle that retains the advantages of the earlier similar structures but that avoids their deficiencies. Namely, one that can be folded up and opened out with much fewer movements, that can be produced using fewer and simpler components as compared to the more developed types, and, besides this, one that remains mobile in folded up state, in other words it can be moved around without carrying it by rolling. It is also at least one that when dismantling the front part of the frame containing the front wheel should be rotatable to beside the part containing the rear wheel, so that the axles of the two wheels fall in a single common line (coincide), because this makes rolling possible when the bicycle is folded up. Furthermore, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.